Electric switch



Se t. 27 1927.

p D. R. DAVIES ELECTRIC SWITCH Filed Feb. 1, 1924 Fig. l.

INVENTOR Z Z M m fl am I Dav id R. Davies.

BY A! ATTORNEY Patented Sept. 27, 1927.

UNITED STATES DAVID EEGINALD' Davies, on ivrancnnsrn'n; ENGLAND, As'srcrivoit iro fwnsrrme- HOUSE nnno'rnro & MANUFACTURING COMPANY, A CORPORATION or IPEI\T1\TJSYL- vnNIA.

ELECTRIC, 'swi'rcn.

Application filed February 1, 1924, Serial No. 689,884, and-in Great Britain February 15, 1923.

My invention relates to electric switches and particularly to switches of the kind commonly known as oil break switches wherein the contacts between which'the circuit is made and broken are located under the surface of oil contained within a suitable tank or casing.

According to my invention, the switch tank is provided with a lid which can be raised to give access to the switch for inspection or other purposes and a movable conductor is provided within the tank which is connected to earth. A device is furthermore provided in operative association with the lid of the tank whereby the conductor is maintained out of cont-act with the switch terminal so long as the lid of the tank is in its closed position, but when the lid is raised to open the tank and permit access to the switch, the device is released to permit the earthed conductor to make connection with a switch contact and so provide a connection to earth of the conductor to which said contact is con nected.

In order that the invention may be clearly understood, it will now be described with reference to the accompanying drawings which illustrate an application of the invention to an isolating switch of the type that can be associated with oil circuit breakers in ironclad switch gear;

Figs. 1 and 2 are sectional elevations of a switch device with certain parts thereof in different positions.

In the example shown in the drawings, the device includes conductors 1 leading to other devices such as circuit breakers and busbars (not shown) and a main incoming or outgoing conductor 2 such as a cable which is adapted to be connected by the switch to either of the conductors 1. The

.switch comprises a pair of fixed contact at 9 and connected to the blade members by levers 10 and links 11. Any desired means, such as the manually retractile bolts 12 providedon the levers 10 and coopertirely removable so as to give access to the switch. The conductor which is adapted to earth the contact jaws 3 and the conductor 2 when the lid 1% is opened consists of a contact 15 secured to the lower end of a rod 16 slidably mounted in a fixed support 17 so that it may engage within the contact jaw 3. The fixed support is connected to earth by mounting it on the tank or by other suitable earth connection. A twoarmed lever 18 is pivoted on a fixed support 19 and one end of it operatively engages with the upper end of the sliding rod 16. At the other end of the lever 18 is mounted a roller 20 that can be engaged by a projection 21 provided on the underside of the removable lid 14 of the switch casing. A spring 22 connects the fixed support 17 to the lever 18 for normally urging the contact 15 towards the contact jaw 3.

With the arrangement above described, it will be seen that, when the lid is raised, the spring 22 will'be permitted to move the arm of the pivoted lever to which it is connected whereby the contact 15 engages and earths the contact aw 3, this position being shown in Fig. 2.

When the lid 14 is replaced, the projection 21 thereon engages with the roller 20 and thereby raises the sliding rod 16 against the action of the spring 22, the contact jaw 3 being thus disconnected from earth, this position being shown in Fig. 1.

It will usually be arranged by means of known interlocking devices (not shown) that the lid of the tank cannot be raised until the switch blades 4: have been opened and have disconnected the conductors 1 and 2.

It is to be understood that the invention is the type described but may be applied to any type of oil immersed switch; and that variations in detail may be made without departing from the scope of the invention.

I claim as my invention:

1. Switch mechanism comprisingra housing, a movable cover for the housing, conductor terminals within the housing, a movable switch member for connecting the said terminals, and means independent of the switch member and controlled by the cover' for conductively, connecting one of the terminals to earth when the cover is moved to its open position.

2. Switch mechanism comprising a housing, a movable cover for the housing, conductor terminals within the housing, a movable switch member for connecting the said terminals, and movable means independent of the switch member and normally conductively connecting one of the said terminals to earth adapted to be retained in inoperative position by the cover when the latter is in its closed position.

3. Switch mechanism comprising a housing, a movable cover for the housing, con ductor terminals within the housing, a movable switch member for connecting the said terminals, and a movable switch member independent of the said'switch member and controlled by the cover for connecting one of the terminals to the housing when the cover is in itsopen position.

In testimony whereof, I have hereunto subscribed my name this ninth day of January 1924.

DAVID REGINALD DAVIES. 

